An Active Matrix Organic Light Emitting Diode (AMOLED) display has been widely applied due to its wide angle of view, good color contrast effect, high response speed, low cost and other advantages. However a drift in threshold voltage and the consequential non-uniformity ire the display of the entire image may occur due to the problems of non-uniformity and instability of a Thin Film Transistor (TFT) back panel in a process flow.
Moreover the number of transmission lines of power supplies to power respective pixel circuits has been constantly increasing with the increasingly larger sizes of AMOLEDs, so that there may be more serious attenuation of voltage across a transmission line of a power supply for an AMOLED larger in size, thus degrading the non-uniformity of display.